DE2921859A1 - MULTI-WIRE LOW VOLTAGE CABLE WITH RADIO-NETWORKED ADERISOLATION - Google Patents

Description

SIEMENS AKTIENGESELLSCHAFT Our reference Berlin and Munich VPA 79 P 4710 BRD

Multi-core low-voltage cable with radiation- linked core insulation

The invention is in the field of electrical cables and lines and deals with material technology Further development of plastic-insulated low-voltage cables.

In the low voltage range (up to 6 kV) the tried and tested Earth cable replaced very early by plastic-insulated cable. While in Germany initially Cables with an extruded core insulation made of polyvinyl chloride have found their way into other countries Cable with insulation from networked! Polyethylene or ethylene-propylene rubber are used ("Slektrizitätswirtschaft", 1976, issue 8, page 173 ff.) Recently, low-voltage cables with insulation made of cross-linked polyethylene are also being used in Germany used (BBC-Nachrichten, 1975, issue 7, page 431 ff). In the manufacture of such cables the core insulation becomes in all after its extrusion

Zm 3 Lo / May 23, 1979

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Usually chemically cross-linked, whereby pressure and heat are applied will. But it is also known that the core insulation of low-voltage cables by means of high-energy To network rays ("Drahtwelt", 1976, issue 9, page 353; "Elektrizitätswirtschaft", 1973, issue 18, Page 640 ff.).

Cast resin fittings are predominantly used for the assembly of plastic-insulated low-voltage cables. With regard to the non-polar molecular structure of both thermoplastic and crosslinked For cables with polyethylene core insulation, polyethylene special casting resins must be used, to ensure good adhesion of the cast resin body to the core insulation ("electricity industry", 1976, No. 8, page 176;, "BBC-Nachrichten", 1975, No. 7, page 432). It has been shown that the liability problem occurs to a greater extent in the case of core insulation made of radiation-crosslinked polyethylene.

The invention is based on the object for multi-core low-voltage cables with an extruded Core insulation on the basis of a radiation cross-linked Polymers to create an insulating mixture that has good adhesion properties to casting resins,

as they are used to manufacture cast resin fittings on 1 ~ kV • Cables are common.

To achieve this object it is provided according to the invention that a polymer is used as the insulating mixture will that

a) from a copolymer of ethylene and a comonomer containing polar groups with a comonomer content of 2 to 25 % or

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b) from a mixture of polyethylene and a copolymer of ethylene and a comonomer containing polar groups with a comonomer content of 2 to 25 % based on the mixture or

c) a thermoplastic from a mixture of 75 to 95 wt .-% polyethylene with 2 to 25 wt -.% atactic polypropylene or polyisobutylene, or polybutene, or non-crosslinked or non-vulcanized ethylene-propylene or ethylene-propylene-diene or natural or Styrene-butadiene or butyl or polybutadiene rubber

and that with a filler such as chalk, kaolin or talc in an amount of 10 to 100, preferably 30 to 60 parts by weight is enriched for 100 parts by weight of the polymer.

In the case of an insulating mixture formed in this way, the mixture differs from ethylene or polyethylene Components (comonomer, resin, filler) the non-polar character of the surface of radiation-crosslinked polyethylene insulation canceled, so that excellent adhesion to the casting resins customary for cable fittings is present, in particular also for casting resins such as those used for low-voltage cables with core insulation made of polyvinyl chloride can be used.

The comonomer used in the context of the invention is preferably a vinyl acetate. It but other comonomers such as ethyl acrylate, vinyl propionate, vinyl butyrate, acrylic acid, Acrylic acid esters, methacrylic acid and methacrylic acid esters are suitable. Copolymers or terpolymers can also be used can be used from ethylene with two or more polar comonomers.

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The insulation mixture provided according to the invention can contain further additives such as those for insulation mixtures Are common, especially color pigments and stabilizers such as antioxidants and metal deactivators ren.

An embodiment of the new low-voltage cable is shown in the figure.

The figure shows a four-core low-voltage cable in which each of the cores 1 to 4 consists of a solid sector conductor 5 and an extruded plastic insulation 6 consists. The four cores stranded with each other are surrounded by the inner jacket 7 and the outer jacket 8 made of polyvinyl chloride.

The core insulation 6 is a radiation-crosslinked insulation, for which the following applies Mixtures have proven suitable: 20

Mix 1:

100.0 parts of ethylene vinyl acetate copolymer with a

Vinyl acetate content of 8.7 % 40.0 parts of chalk

0.5 parts of polym. 2,2,4-trimethyl-1,2-dihydroquinoline

(Anox HB)

Mix 2:

90.0 parts of ethylene homopolymer (polyethylene) 10.0 parts of ethylene-propylene rubber, uncrosslinked 40.0 parts of chalk

0.5 part of polym, 2,2,4-trimethyl-1,2-dihydroquinoline (Anox HB)

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85.0 parts polyethylene
15.0 parts of ethylene vinyl acetate copolymer with a vinyl acetate content of 60 % 35.0 parts of chalk

0.6 parts of polym. 2,2,4-trimethyl-1,2-dihydroquinoline (Anox HB)

Cable cores were initially used to check the adhesive strength of casting resins on the new core insulation manufactured with extruded, radiation crosslinked insulation. Then there were longitudinal strips from the back of the sector of the veins removed and to assess the cast resin adhesive properties after a peel strength test Subjected to curing of a cast resin gate. It was found that the adhesive strength was higher in all cases than 25 N / 15 mm. By conditioning the core insulation, i. H. by storage at room temperature for 24 hours and subsequent storage at 80 ° C. for 24 hours, the adhesive strength could exceed 40 N / 15 mm can be increased.

2 claims
1 figure

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Claims (2)

- / Γ - VPA 79 P 4710 BRD patent claims ό / ιMulticore medicated tensioning cable with an extruded Core insulation based on a radiation-crosslinked polymer, characterized in that that as a polymer a) a copolymer of ethylene and a comonomer containing polar groups with a comonomer content of 2 to 25 % or b) a mixture of polyethylene and a copolymer of ethylene and one having polar groups ■ Comonomer with a comonomer content based on the mixture of 2 to 25 % or c) a mixture of 75 to 95 wt .-% polyethylene with 2 to 25 wt -.% atactic polypropylene or polybutene or polyisobutylene or unvernetztein or unvulcanized ethylene-propylene or ethylene-propylene terpolymer or natural or styrene butadiene or Polybutadiene or butyl rubber is used with a filler such as chalk, kaolin or talc in an amount of 10 to 100, preferably 30 to 60 parts by weight is enriched for 100 parts by weight of the polymer. 2. Multi-core low voltage cable according to claim 1, characterized in that the Polymer contains conventional additives such as color pigments and stabilizers. 030048/0515 ORIGINAL INSPECTED